Machine for curving sheets, in particular to obtain conical workpiece and the like



Nov. 29, 1966 Filed Oct. 31, 1963 P. R. BOLDRINI 3,287,953

MACHINE FOR CURVING SHEETS, IN PARTICULAR TO OBTAIN GONICAL WORKPIECE AND THE LIKE 5 Sheets-Sheet 1 PRIOR 14 r PRIOR ART Nov. 29, 1966 P. R. BOLDRINI 3,287,953

MACHINE FOR CURVING SHEETS, IN PARTICULAR TO OBTAIN CONICAL WORKPIECE AND THE LIKE Filed Oct. 51, 1963 5 Sheets-Sheet 2 Filed Oct. 51, 1963 Nov. 29, 1966 P.R. BOLDRlNl MACHINE FOR CURVING SHEETS, IN PARTICULAR TO United States Patent 2 Claims. (Cl. 72-171 It is an object of the present invention to provide an improved machine to curve metal plates, in particular to obtain conical workpieces and the like.

It is well known that machines employed to curve and roll sheets, of the type with symmetrical and asymmetrical rolls and with or without capacity to execute the initial bending also called prebending, in order to effect curving of cones have to tilt one or more rolls, motorized or not, as well as to place one or more supplementary rolls on the uprights of the machine; these rolls have the function of imparting a forward angular motion to the sheet from which the cone is developed; the aforesaid rolls by favouring the forward motion of the greater circumference and retarding the forward motion of the lesser circumference, establish ideal conditions for obtaining the conical bending.

In addition, the aforesaid supplementary rolls prevent the sheet from slipping out of the machine because of the component which originates along the ideal axis of the cone during the rolling of the cone itself.

But these supplementary rolls as devised for machines actually in use, do not permit the provision of cones below a certain diameter because of the long distance between these rolls. Further, it must be observed that the angle formed by their axis with that of the lower rolls varies according to the tilting or inclination of these rolls, and in certain cases this may cause deformation of the edges of plates being bent.

Another obvious disadvantage in present day machines, with their supplementary rolls mounted on fixed uprights, is the necessity of dismounting these supplementary rolls in order to extract the cones when the process of bending is completed.

All these and other disadvantages are eliminated by the machine according to the present invention, which is characterized essentially in that its own supplementary rolls are mounted on the bearings of the forming (lower) rolls, which can be tilted. By this improvement the following advantages are reached:

(1) Compared with the machines actually in use having their supplementary rolls mounted on fixed uprights, it allows the formation of cones considerably smaller, since in the present invention the rolls are mounted closer to each other on the bearings of the lower rolls which can be tilted.

(2) The angle between the axes of the supplementary rolls and the axis of the forming rolls which can be tilted is always constant (90). Consequently the thickness of the plate being formed, lies entirely against supplementary rolls so avoiding any deformation of the edges. In the machines used at present only part of the thickness of the plate being bent lies against supplementary rolls, and consequently the stress arising may cause deformation of the edges of the workpiece.

(3) With the machines used up to now, after completion of the cone it is necessary to take off the supplementary rolls in order to take out the cone.

With the improved machine the finished cone is taken out of the machine by simply lowering the bearings of the forming rolls together with the supplementary rolls they carry.

3,287,953 Patented Nov. 29, 1966 "ice This improved machine will now be more fully described in one particular case which does not limit it to this example, on the basis of the enclosed drawings, wherein:

FIGS. 1 to 5 illustrate certain parts of a plate bending roll on which is mounted a known type of conical bending device.

FIGS. 6 to 10 illustrate the corresponding parts of the same plate bending machine provided with a conical bending device according to the present invention.

More exactly:

FIG. 1 shows a partial vertical section of a known machine with the rear upright carrying the supplementary rolls.

FIG. 2 is a part elevation view with the plate being formed between the rolls.

FIG. 3 shows on enlarged scale, a part of the plate being formed, which lies against supplementary rolls of a known machine.

FIG. 4 shows a plan view of FIG. 2.

FIG. 5 is the same view as in FIG. 1 with the supplementary rolls drawn in broken outline to indicate they have to be taken otf when the finished workpiece is to be extracted As pointed out before, FIGS. 6 to 10 show the improved machine;

More exactly:

FIG. 6 corresponding to FIG. 1 shows that according to the present invention, the supplementary rolls are mounted on the bearing of the tiltable rolls instead of on the uprights of the machine.

FIGS. 7, 8, 9 correspond respectively to FIGS. 2, 3, 4 and show the features of the improved machine as explained further.

FIG. 10 corresponding to FIG. 5, shows how supplementary rolls placed on the bearing of the tiltable rolls of the machine according to the present invention, do not have to be taken off for extraction of the completed workpiece.

With reference to the above two sets of drawings the fixed upright 1 with its three bending rolls 2-3-3 mounted on respective bearings 455 are shown.

Top roll 2 has its own fixed bearing 4 while the lower rolls 3-3 are carried by respective supports 5-5 adjustable along their guides 6-6 and can be tilted (FIG. 2 and 87) for bending the plate 7.

In the known machines, on the uprights 1 are mounted the fixed rolls 88, and their geometric axes xx are contained in a vertical plane and equally tilted towards the center line, which meets the longitudinal axis w of the fixed roll 2. When supplementary rolls 8 are mounted on the fixed upright 1 and the lower rolls 3 have to be tilted in order to execute the job required, the angle or is more than and the result, shown in FIG. 3, is that the plate 7 being bent, will never lean against the supplementary rolls for the whole portion of its thickness. As shown at K of the above mentioned FIG. 3 this may cause deformation of the workpiece.

According to the present invention and as illustrated in FIGS. 6 to 10, supplementary rolls 8 are mounted on the bearings 5 of the rolls 3. Said rolls 8 are still inclined towards the center line, but their axis x-x are exactly at 90 (angle a) to the axes of the rolls 3.

As a consequence the angle a remains at 90, whatever the inclination of the rolls 3, and the thickness of the plate 7 lies always entirely against the external surface of supplementary rolls 8.

This is clearly shown in FIG. 8. Furthermore attention is drawn to the fact that when bending operation is completed and the workpiece is to be extracted,

there is no need to take olf the supplementary rolls as is normally done with the known machines.

In the improved machine it is only required to lower the supports of the rolls 3 along their guide 6 as supplementary rolls 8 also will be automatically lowered andwill not hamper the extraction of the workpiece.

Another improvement is that the minimum distance D1 (in the improved machine) being much smaller than the distance D2 (in the known machine), FIG. it will be possible to make bending of cones having lesser diameters.

From the above description, those skilled in the art will clearly understand the useful, industrial advantages obtained with the present invention. Said advantages will obtain a better and substantially faster processing, an easy operation and the possibility of covering a wider range of jobs.

Although only one embodiment of the invention has been described and illustrated, nevertheless constructional changes are possible without departing fromthe scope of this invention; thus for example the rollers 8 may be smooth or knurled, stationary or rotating, fixed or removable, tiltable together with their bearings or independently, etc.

4 I claim: I 1. A machine for bending metal sheets comprising a frame provided with a pair of vertically arranged guides,-

a bending roll having a bearing fixed on said frame, a pair of adjustable rolls each provided with a support adjustable in said guides, said supports being tiltable so that the axes of said last-named rolls may be angularly related to the axis of said bending roll, and a pair of supplementary rolls respectively mounted on said supports and adjustable and tiltable therewith.

2. A machine according to claim 1 wherein the axes of said supplementary rolls are inclined toward said bending roll and the last-named axes are respectively arranged at all times at an angle of to the axesof said adjustable rolls.

References Cited by the Examiner UNITED STATES PATENTS Re. 5,409 5/ 187 3 Tomlinson 72-173 1,338,946 5/1920 Mayers 72 -l7l 1,435,041 11/1922 Zimmer 72171 CHARLES W. LANHAM, Primary Examiner. H. D. HOINKES, Assistant Examiner. 

1. A MACHINE FOR BENDING METAL SHEETS COMPRISING A FRAME PROVIDED WITH A PAIR OF VERTICALLY ARRANGED GUIDES, A BENDING ROLL HAVING A BEARING FIXED ON SAID FRAME, A PAIR OF ADJUSTABLE ROLLS EACH PROVIDED WITH A SUPPORT ADJUSTABLE IN SAID GUIDES, SAID SUPPORTS BEING TILTABLE SO THAT THE AXES OF SAID LAST-NAMED ROLL, AND A PAIR OF RELATED TO THE AXIS OF SAID BENDING ROLL, AND A PAIR OF SUPPLEMENTARY ROLLS RESPECTIVELY MOUNTED ON SAID SUPPORTS AND ADJUSTABLE AND TILTABLE THEREWITH. 